[v7,08/10] iommu/dma-reserved_iommu: iommu_msi_mapping_desc_to_domain

Message ID 1461084994-2355-9-git-send-email-eric.auger@linaro.org
State New
Headers show

Commit Message

Auger Eric April 19, 2016, 4:56 p.m.
This function checks whether
- the device emitting the MSI belongs to a non default iommu domain
- the iommu domain requires the MSI address to be mapped.

If those conditions are met, the function returns the iommu domain
to be used for mapping the MSI doorbell; else it returns NULL.

Signed-off-by: Eric Auger <eric.auger@linaro.org>

---
 drivers/iommu/dma-reserved-iommu.c | 19 +++++++++++++++++++
 include/linux/dma-reserved-iommu.h | 18 ++++++++++++++++++
 2 files changed, 37 insertions(+)

-- 
1.9.1

Comments

Auger Eric April 21, 2016, 8:40 a.m. | #1
Hi Robin,
On 04/20/2016 07:19 PM, Robin Murphy wrote:
> On 19/04/16 17:56, Eric Auger wrote:

>> This function checks whether

>> - the device emitting the MSI belongs to a non default iommu domain

>> - the iommu domain requires the MSI address to be mapped.

>>

>> If those conditions are met, the function returns the iommu domain

>> to be used for mapping the MSI doorbell; else it returns NULL.

>>

>> Signed-off-by: Eric Auger <eric.auger@linaro.org>

>> ---

>>   drivers/iommu/dma-reserved-iommu.c | 19 +++++++++++++++++++

>>   include/linux/dma-reserved-iommu.h | 18 ++++++++++++++++++

>>   2 files changed, 37 insertions(+)

>>

>> diff --git a/drivers/iommu/dma-reserved-iommu.c

>> b/drivers/iommu/dma-reserved-iommu.c

>> index 2522235..907a17f 100644

>> --- a/drivers/iommu/dma-reserved-iommu.c

>> +++ b/drivers/iommu/dma-reserved-iommu.c

>> @@ -17,6 +17,7 @@

>>

>>   #include <linux/iommu.h>

>>   #include <linux/iova.h>

>> +#include <linux/msi.h>

>>

>>   struct reserved_iova_domain {

>>       struct iova_domain *iovad;

>> @@ -332,3 +333,21 @@ unlock:

>>   }

>>   EXPORT_SYMBOL_GPL(iommu_put_reserved_iova);

>>

>> +struct iommu_domain *iommu_msi_mapping_desc_to_domain(struct msi_desc

>> *desc)

>> +{

>> +    struct device *dev;

>> +    struct iommu_domain *d;

>> +

>> +    dev = msi_desc_to_dev(desc);

>> +

>> +    d = iommu_get_domain_for_dev(dev);

>> +

>> +    if (!d || (d->type == IOMMU_DOMAIN_DMA))

>> +        return NULL;

>> +

>> +    if (iommu_domain_get_attr(d, DOMAIN_ATTR_MSI_MAPPING, NULL))

>> +        return NULL;

> 

> Yeah, I don't see why we couldn't just use

> 

> if (domain->ops->capable(IOMMU_CAP_INTR_REMAP))

>     return NULL

I don't think this works. This will lead to MSI iommu mapping on x86
when irq_remapping is disabled. To be further checked though.

Eric
> 

> there instead.

> 

>> +

>> +    return d;

>> +}

>> +EXPORT_SYMBOL_GPL(iommu_msi_mapping_desc_to_domain);

>> diff --git a/include/linux/dma-reserved-iommu.h

>> b/include/linux/dma-reserved-iommu.h

>> index 8722131..8373929 100644

>> --- a/include/linux/dma-reserved-iommu.h

>> +++ b/include/linux/dma-reserved-iommu.h

>> @@ -19,6 +19,7 @@

>>   #include <linux/kernel.h>

>>

>>   struct iommu_domain;

>> +struct msi_desc;

>>

>>   #ifdef CONFIG_IOMMU_DMA_RESERVED

>>

>> @@ -70,6 +71,17 @@ int iommu_get_reserved_iova(struct iommu_domain

>> *domain,

>>    * if the binding ref count is null, destroy the reserved mapping

>>    */

>>   void iommu_put_reserved_iova(struct iommu_domain *domain,

>> phys_addr_t addr);

>> +

>> +/**

>> + * iommu_msi_mapping_desc_to_domain: in case the MSI originates from

>> a device

>> + * upstream to an IOMMU and this IOMMU translates the MSI transaction,

>> + * this function returns the iommu domain the MSI doorbell address

>> must be

>> + * mapped in. Else it returns NULL.

>> + *

>> + * @desc: msi desc handle

>> + */

>> +struct iommu_domain *iommu_msi_mapping_desc_to_domain(struct msi_desc

>> *desc);

>> +

>>   #else

>>

>>   static inline int

>> @@ -93,5 +105,11 @@ static inline int iommu_get_reserved_iova(struct

>> iommu_domain *domain,

>>   static inline void iommu_put_reserved_iova(struct iommu_domain *domain,

>>                          phys_addr_t addr) {}

>>

>> +static inline struct iommu_domain *

>> +iommu_msi_mapping_desc_to_domain(struct msi_desc *desc)

>> +{

>> +    return NULL;

>> +}

>> +

>>   #endif    /* CONFIG_IOMMU_DMA_RESERVED */

>>   #endif    /* __DMA_RESERVED_IOMMU_H */

>>

>

Patch

diff --git a/drivers/iommu/dma-reserved-iommu.c b/drivers/iommu/dma-reserved-iommu.c
index 2522235..907a17f 100644
--- a/drivers/iommu/dma-reserved-iommu.c
+++ b/drivers/iommu/dma-reserved-iommu.c
@@ -17,6 +17,7 @@ 
 
 #include <linux/iommu.h>
 #include <linux/iova.h>
+#include <linux/msi.h>
 
 struct reserved_iova_domain {
 	struct iova_domain *iovad;
@@ -332,3 +333,21 @@  unlock:
 }
 EXPORT_SYMBOL_GPL(iommu_put_reserved_iova);
 
+struct iommu_domain *iommu_msi_mapping_desc_to_domain(struct msi_desc *desc)
+{
+	struct device *dev;
+	struct iommu_domain *d;
+
+	dev = msi_desc_to_dev(desc);
+
+	d = iommu_get_domain_for_dev(dev);
+
+	if (!d || (d->type == IOMMU_DOMAIN_DMA))
+		return NULL;
+
+	if (iommu_domain_get_attr(d, DOMAIN_ATTR_MSI_MAPPING, NULL))
+		return NULL;
+
+	return d;
+}
+EXPORT_SYMBOL_GPL(iommu_msi_mapping_desc_to_domain);
diff --git a/include/linux/dma-reserved-iommu.h b/include/linux/dma-reserved-iommu.h
index 8722131..8373929 100644
--- a/include/linux/dma-reserved-iommu.h
+++ b/include/linux/dma-reserved-iommu.h
@@ -19,6 +19,7 @@ 
 #include <linux/kernel.h>
 
 struct iommu_domain;
+struct msi_desc;
 
 #ifdef CONFIG_IOMMU_DMA_RESERVED
 
@@ -70,6 +71,17 @@  int iommu_get_reserved_iova(struct iommu_domain *domain,
  * if the binding ref count is null, destroy the reserved mapping
  */
 void iommu_put_reserved_iova(struct iommu_domain *domain, phys_addr_t addr);
+
+/**
+ * iommu_msi_mapping_desc_to_domain: in case the MSI originates from a device
+ * upstream to an IOMMU and this IOMMU translates the MSI transaction,
+ * this function returns the iommu domain the MSI doorbell address must be
+ * mapped in. Else it returns NULL.
+ *
+ * @desc: msi desc handle
+ */
+struct iommu_domain *iommu_msi_mapping_desc_to_domain(struct msi_desc *desc);
+
 #else
 
 static inline int
@@ -93,5 +105,11 @@  static inline int iommu_get_reserved_iova(struct iommu_domain *domain,
 static inline void iommu_put_reserved_iova(struct iommu_domain *domain,
 					   phys_addr_t addr) {}
 
+static inline struct iommu_domain *
+iommu_msi_mapping_desc_to_domain(struct msi_desc *desc)
+{
+	return NULL;
+}
+
 #endif	/* CONFIG_IOMMU_DMA_RESERVED */
 #endif	/* __DMA_RESERVED_IOMMU_H */